The primary purpose of the Antigen and Antibody Production Shared Resource is to provide a timely and economical means by which GST-fusion protein, mouse polyclonal and monoclonal antibodies, and ascites can be produced for members of the San Antonio Cancer Institute. Availability of high quality antibodies represents a critical element for the understanding of gene function and in subsequent translational applications. SACI members identify or work on new genes that are important for cancer predisposition, progression and prognosis. GST fusion proteins are superior for the production and selection of high quality antibodies since the fusion protein can be purified through simple manipulation. Most purified GST-fusion proteins stimulate excellent immunoresponses in mice. Although GST-fusion proteins are most commonly used as antigens by the core, other approaches can be used if necessary or preferred by the investigator. The core is directed by Barbara A. Christy, Ph.D., who has experience in the production of a variety of polyclonal and monoclonal antibodies. Her laboratory has created, purified and used a number of GST-fusion proteins and His-tagged proteins in bacteria and expressed several proteins in baculovirus. These proteins have been used for polyclonal antibody production, monoclonal antibody production, antibody affinity purification, DNA binding studies, protein-protein interaction studies, expression library screening and as substrates in protein kinase assays. In addition, Dr. Christy's lab is experienced in the use of these antibodies for the analysis of protein expression and function in mammalian cells, immunofluorescence, immunohistochemistry, immunoprecipitation and subcellular fractionation. Specific services provided by this Shared Resource include GST-fusion protein production, mouse polyclonal antisera production, mouse monoclonal antibody production, ascites production, the use of these reagents in characterizing specific gene products, and cryopreservation of hybridoma lines and antibody stocks.